Relation of fall stream‐flow to spring runoff

In the prediction of spring runoff from precipitation‐records or snow‐surveys, one of the factors which seems to require consideration is the amount of water held in ground‐storage. The determination of the quantity of water in ground‐storage is a difficult problem involving soil‐sampling, measurements of ground‐water wells, and measurements of the flow of small streams and springs. It has occurred to the writer that selected stream‐flow records for either the late fall or early spring might provide a better index of the ground‐water available for spring runoff than that obtained by other methods. This would involve a comparison of runoff in the fall with runoff in the spring, and might eliminate uncertainties in the relation of a reservoir‐level in the fall with runoff in the spring. Such a method would be especially desirable because of the availability of stream‐flow records. The discussion which follows is more an explanation of the method to be used than an attempt to develop an accurate formula for the prediction of spring runoff.